


3 Days Of The Etherial Moon

by Ayami (Syrica)



Series: Setleth Week 2019 [6]
Category: Fire Emblem Three Houses
Genre: F/M, It’s a very special boy’s birthday!, Post-Game, Regular spoilers for Flayn and Seteth’s supports but that’s standard fare by now
Language: English
Status: Completed
Published: 2020-01-04
Updated: 2020-01-04
Packaged: 2021-02-27 15:14:49
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 2,510
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22119220
Author URL: https://archiveofourown.org/users/Syrica/pseuds/Ayami
Summary: It’s Seteth’s birthday but there’s also Saint Cichol Day, Establishment Day and the anniversary of someone’s death all within the span of 3 days
Relationships: My Unit | Byleth/Seteth
Series: Setleth Week 2019 [6]
Series URL: https://archiveofourown.org/series/1577923
Comments: 12
Kudos: 80





	3 Days Of The Etherial Moon

**Author's Note:**

> Setleth Week Day 6: St. Cichol Day/Seteth's Birthday
> 
> I am so so late D:

The last few days of the Ethereal Moon were hectic for everyone for many reasons but for Byleth and Seteth, a cluster of three days were a particular rollercoaster of emotions. 

On the 25th day of the Etherial Moon, they celebrated with everyone else the founding day of Garreg Mach Monastery, hosting for the students of the academy the annual ball. Seteth, as usual, spent most of his time as a chaperone, reminding students who danced particularly close together to “leave room for the goddess”.  
Byleth often stood to the side and with an amused smile, watching him endlessly flit about. She theorized that all of his energy that once went into hovering over Flayn had found a new outlet in fretting over the students entrusted in the academy’s care- so much so that his reputation around the school had taken to shifting from “strict and difficult to approach” to an “easier to approach but similarly strict father figure”. Fatherhood suited him, she thought, and she silently mused about the possibly of giving him someone new to dote over. She knew that was years off, but it couldn’t hurt to _imagine_.

When the commotion of the ball died down, they had themselves a tradition of returning to the goddess tower, where they had first become engaged. Try as they might to make the visit a short trip down memory lane, they nearly always succumbed to sentimentality: melting into a pile of sugary-sweet affections, and effectively renewing their vows every year between soft coos and kisses.   
This often had the unintended effect of embarrassing any students that had attempted to sneak out there, running away as if they’d walked in on their parents being mushy.

  
“Do you think they’ll ever learn?” Byleth said, sighing after pulling away from their kisses after the _third_ pair of students that night hard-pivoted away from the tower upon stumbling on the couple.   
He laughed softly, leaning his forehead against hers, then he took one of her arms and guided her hand towards his face, brushing his lips against the skin on the back, “Will _we_?”  
Byleth made a face of false contemplation, “No, I don’t think so.” She answered after a moment, breaking out into a smile and leaning in to take his lips once again, her smile spreading to his mouth through the contact.

On the 26th day of the Ethereal Moon, the mood was quite a bit more somber. The anniversary of Jeralt’s death never passed by without a trip to his grave, and Byleth made the tradition of buying a bottle of booze and emptying it between herself and Alois there.  
The first time the anniversary passed, Seteth had insisted on following her to his grave where he proceeded to ask her father for her hand in marriage. Jeralt couldn’t respond of course, but Seteth couldn’t help trying to do it the old school way regardless.

The years after that, he generally accompanied her to the grave, said a few words, and then left Byleth and Alois to drink in peace. They both had deep connections with the man and Seteth felt like he had little right to be there given that he knew very little of him. Though originally, the drinking they engaged in while he was gone worried him a little, he very quickly learned that Byleth had indeed inherited her father’s constitution and rarely came away more than a little bit off-balance.   
Unbeknownst to him, while she _could_ hold her liquor, she had actually chosen to instead begin dumping some of her drink onto the grave itself, to honor her father, for sure, but also to insure she would not be hung over for the next day.

The 27th day of the Etherial Moon was both Saint Cichol day and Seteth’s birthday. That meant that the couple’s day began with a service and then about an hour of Byleth needing to practically _order_ Seteth to take the day off. A feat which was much easier to accomplish when Flayn managed to return for a visit, but still difficult nonetheless.

“Brother I must _insist_!” Flayn’s adamant voice was heard down the halls as the two green haired girls tailed the darker green haired man down towards his office. “Why must we do this every year?” She sounded positively exhausted. 

“Flayn, I appreciate the effort, but every year I still have _work_.” He picked up speed as he not-so-subtlety tried to escape the two people closing in on either side of him, “the date of my birth does not change this.”

“Yes but the work will be there tomorrow, you only have one birthday a year!” she broke out into a skip in order to keep up with him, grabbing onto one of his sleeves as she attempted to keep with his rising pace.

Seteth quickly glanced at his restrained arm, “ _Flayn_.” He admonished in a tone that all too clearly communicated that he was indeed her father. Sometimes Byleth wondered how Claude had figured it out so quickly, and other times, like this, when she did not.

“ _Brother_.” Flayn returned in a tone mocking his own, refusing to relinquish the sleeve.

Before Seteth could open his mouth, he felt a tug on his other sleeve, and looked over to see Byleth, holding it in mirror of his daughter, though admittedly, much more straight-faced. “ _You two…_ ”  
He finally stopped in his tracks and sighed, taking stock of the situation he currently found himself in: his daughter and his wife very publicly restraining him in the middle of a hallway because it was his birthday. 

Byleth took his pause as an opportunity to speak, “The way I see it, you have two options.” She spoke slowly, like she was explaining a difficult subject to one of her students, “you could either: continue barreling at an unruly pace towards your office with two people attached to you in order to sit down at a desk and do _paperwork_ , or ” she punctuated the “or” by curling her arm around the rest of his, something his daughter also mirrored, as if he wasn’t already trapped enough. “You could retire for the day and spend the rest of the afternoon with your family, who are all too willing to shower you with their attention.” 

_What an unfair choice to make._ He thought.

He shook his head, “When you put it like that, I very well cannot refuse, can I?”

Flayn jumped up, letting go of his arm, “Yes! Let us go to our quarters, the professor and I have things set up there.”

“You wha-” he managed to get out before he found himself getting dragged across the hall by a rather strong girl. “What have you prepared?” He turned to look at Byleth for any sort of explanation but she merely shrugged and watched him continue to be hauled away by his daughter.

  
By the time they reached the door, Flayn had relinquished her hold on her father. She excitedly pulled out her personal key to the room and unlocked it, hurrying all of them through the entry.

As soon as they made it inside, she made a beeline towards her room, leaving Byleth to guide Seteth towards the seats surrounding the fire place, which she promptly lit with a flick of her hand. He could smell the food on the counter behind them but before he could turn to ask what it was, Flayn emerged from her room with a small package in her hands, immaculately wrapped in reflective wrapping paper, and adorned with a delicately tied bow.

“And what might this be?” He asked as he took his place on his seat, an endeared simile making its way onto his face as he tilted his head curiously in her direction. 

“You will just have to open it yourself and see.” She said playfully grinning as she handed him the box.

He took the item which was handed to him and deftly pulled apart the bow, laying the ribbon on the table beside him. Next he slipped a nail under the seam of the wrapping, and slowly ran it along the line, separating it from the rest of the paper.

“You do not have to be so careful!” She threw her arms into the air, “Just rip it open! The suspense is killing me!”

“I do not wish to make a mess.” Seteth replied calmly, without turning to look at her, rather continuing to disassemble the wrapping paper. She just barely noticed the smile tugging at the corner of his mouth.

She audibly gasped, “You are doing it on _purpo_ -! Oh, there we go.” She stopped when she saw the completely unwrapped box in his hand, and instead moved to focus on his face as he opened it.

Seteth folded the top of the box back to reveal what looked to be a colorful fishing bait inside. “Flayn, is this bait?” He reached in and pulled it out with the intention of examining it closer, when it began wriggling in his hands.

Flayn gave a mischievous giggle when she saw him immediately drop it in surprise.

“Surprise!” She said between her laughter, “It is enchanted to move, you see?” She reached to pick up the small carving, turning it around him her hand while it continued to move rather realistically. “Linhardt showed me how to make these and I have been practicing for nearly a _month_ to get it right! I even spent all my allowance on special paint that doesn’t wear out in water.”

“I see…” he said still a bit mystified at the natural movement of it, he took the item back and examined it himself. The magic imbued in this must have been incredibly impressive, he thought. “This is _lovely_ , thank you Flayn.” He reached out to her, motioning to her to come in and accept his hug. She smiled and complied, leaning down to where he was sitting in his chair and accepting the kiss he placed sweetly on her head.

Afterwards, Seteth looked up and around, “Where is Byleth?”

“Don’t worry I’m still here.” She called from behind him, and he turned around to see her making her way from their shared room, carrying a similarly sized box as Flayn had. _When did she hide something in there, and how did I not notice?_

Shaking his thoughts clear, he returned his attention to her as she strode over in her typical unaffected manner and sat adjacent to him.

“It may seem a bit… _juvenile_ , but…” she prefaced her gift while handing it to him. He couldn’t quite imagine what could possibly warrant an advance notice from her, especially for something that came in a box as small and light as the one currently in his hands. “I hear matching jewelry has become quite fashionable among young couples all over Fódlan.” She finished her explanation as Seteth removed the lid of the box and found a necklace with a hand-crafted charm hung on it. 

_Just one. What happened to the matching half?_ He puzzled as he looked up to Byleth for an explanation, and promptly found one by way of her reaching under the neck of her shirt and pulling out a second, similar chain.

She held out the end of the it so that he could get a better look: on it he could see a charm shaped like a key which was nearly all gold, save for the handle which was adorned with a small, pale emerald.

He looked down at the necklace in his lap, taking the chain between his fingers, he examined his half of the pair. The charm was different from hers. It was a golden lock with a similar emerald on the side. Seteth had, in his mind, assumed that “matching” meant “the same”, but the way that these two different things fit together was more meaningful somehow. Two halves of a whole that didn’t work properly when separated, but when used together they can protect something precious. It was, in a sense, _them_.

He curled his hand around the trinket, and looked back at her. “Thank you, my love.”

“Well? Are you not going to put it on?” Flayn questioned, seating herself on the unoccupied edge of his chair to get a closer look at the shape of the charm. 

“I… suppose that would be appropriate.” He answered, looking to Byleth who nodded at him. “Could you assist me, Flayn?” He asked as he unhooked the clasp at the back and pushed it in her direction. 

“I would _love_ to.” She clapped her hands together in excitement, “Now, hold your hair back.” she commanded, then grasped each end of the chain and moved in front of Seteth. Reaching her arms out, she looped the chain around his neck and fastened it, pulling back to survey her handiwork. “It looks lovely!”

He stood, hand on this new trinket. “Ah, it does? I am glad.” He looked over at Byleth who was absentmindedly fidgeting with her own at her neck, unable to move her eyes from him. He couldn’t help but extend his hand outwards and she couldn’t help but inch closer, reaching out towards his chest to turn his present around in her hand. As she fiddled with the lock around his neck, he heard her let out what sounded like a stifled giggle.

“What is it?” He looked down at her, putting his hand on hers in order to bring her attention back to him.

“Mine is a key, and yours is a keyhole.” She explained though an uneven breathing that approximated laughter.

He blinked, sure of what was so funny. “Do you mean a _lock_ -” He stiffened and Byleth’s giggles continued, paired with Flayn’s own laughter that she muffled through her hands.   
He brought his fingers to pinch the bridge of his nose in a show of only slightly exaggerated annoyance. “My love, was this… did you do this on purpose?”

Byleth reached out, wrapping her hands around his neck, “ _No_ , no, I only just noticed it now, I promise.” She pulled him into a tight hug, her hand resting on the back of his head. 

From his position, lying his head on her shoulder, he could still feel the last of her laughter as she tried to contain it. Just a few years ago, he would’ve never dreamed of hearing such a sound from her- because of him no less- and now he could hear it up close, as she ran her fingers through his hair. “ _Happy birthday Cichol_.” She whispered into his hair, pressing a kiss to the crown of his head.

From behind him, he felt another, smaller, pair of hands wrap around his waist, and the warmth of Flayn’s head resting on his back. “Happy birthday, Father.”

Ordinarily, he would worry about the both of them calling him both names, but he was far to content at the moment to do such a thing. For the time being, he would simply bask in the embrace of his family.

**Author's Note:**

> And then they had to stop hugging real quick for a second cause the food almost burned.


End file.
